CVE-2026-21916
Junos OS: A low privileged user can escalate their privileges so that they can login as root
Description
A UNIX Symbolic Link (Symlink) Following vulnerability in the CLI of Juniper Networks Junos OS allows a local, authenticated attacker with low privileges to escalate their privileges to root which will lead to a complete compromise of the system. When after a user has performed a specific 'file link ...' CLI operation, another user commits (unrelated configuration changes), the first user can login as root. This issue affects Junos OS: * all versions before 23.2R2-S7, * 23.4 versions before 23.4R2-S6, * 24.2 versions before 24.2R2-S3, * 24.4 versions before 24.4R2-S2, * 25.2 versions before 25.2R2. This issue does not affect versions 25.4R1 or later.
INFO
Published Date :
April 9, 2026, 10:16 p.m.
Last Modified :
Oct. 26, 2026, 9:10 p.m.
Remotely Exploit :
No
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-21916
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | HIGH | 8cbe9d5a-a066-4c94-8978-4b15efeae968 | ||||
| CVSS 3.1 | HIGH | [email protected] | ||||
| CVSS 3.1 | HIGH | MITRE-CVE | ||||
| CVSS 4.0 | HIGH | 8cbe9d5a-a066-4c94-8978-4b15efeae968 | ||||
| CVSS 4.0 | HIGH | [email protected] |
Solution
- Upgrade Junos OS to a fixed version.
- Apply security patches and updates.
- Monitor system for unauthorized access.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-21916.
| URL | Resource |
|---|---|
| https://kb.juniper.net/JSA107807 | Mitigation Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-21916 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-21916
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-21916 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-21916 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Translated by [email protected]
Oct. 26, 2026
Action Type Old Value New Value Added Translation Title: Junos OS de Juniper Networks, Description: Una vulnerabilidad de seguimiento de enlace simbólico (Symlink) de UNIX en la CLI de Juniper Networks Junos OS permite a un atacante local, autenticado y con bajos privilegios escalar sus privilegios a root, lo que conducirá a un compromiso completo del sistema. Cuando, después de que un usuario ha realizado una operación CLI específica de ’file link ...’, otro usuario confirma (cambios de configuración no relacionados), el primer usuario puede iniciar sesión como root. Este problema afecta a Junos OS: * todas las versiones anteriores a 23.2R2-S7, * versiones 23.4 anteriores a 23.4R2-S6, * versiones 24.2 anteriores a 24.2R2-S3, * versiones 24.4 anteriores a 24.4R2-S2, * versiones 25.2 anteriores a 25.2R2. Este problema no afecta a las versiones 25.4R1 o posteriores. -
CVE Modified by [email protected]
Jun. 17, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'Juniper Networks', 'product': 'Junos OS', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '23.2R2-S7', 'versionType': 'semver'}, {'status': 'affected', 'version': '23.4', 'lessThan': '23.4R2-S6', 'versionType': 'semver'}, {'status': 'affected', 'version': '24.2', 'lessThan': '24.2R2-S3', 'versionType': 'semver'}, {'status': 'affected', 'version': '24.4', 'lessThan': '24.4R2-S2', 'versionType': 'semver'}, {'status': 'affected', 'version': '25.2', 'lessThan': '25.2R2', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '25.4R1'}], 'defaultStatus': 'unaffected'}] -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 17, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-21916', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-04-10T03:56:11.604149Z'} -
Initial Analysis by [email protected]
Apr. 17, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:o:juniper:junos:23.2:r1:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:23.2:r1-s1:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:23.2:r1-s2:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:23.2:-:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:23.4:r1:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:23.4:-:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:23.4:r1-s1:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:23.2:r2:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:24.2:-:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:24.2:r1:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:23.4:r1-s2:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:23.2:r2-s1:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:23.2:r2-s2:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:23.4:r2:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:23.4:r2-s1:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:23.4:r2-s2:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:23.4:r2-s3:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:24.2:r1-s1:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:24.2:r2:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:23.2:r2-s3:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:23.2:r2-s4:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:23.4:r2-s4:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:24.2:r1-s2:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:24.4:-:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:24.4:r1:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:24.4:r1-s2:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:24.4:r1-s3:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:24.2:r2-s1:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:24.4:r2:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:23.4:r2-s5:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:24.2:r2-s2:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:24.4:r2-s1:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:25.2:-:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:25.2:r1:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:25.2:r1-s1:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:25.2:r1-s2:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:23.2:r2-s5:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:*:*:*:*:*:*:*:* versions up to (excluding) 23.2 *cpe:2.3:o:juniper:junos:23.2:r2-s6:*:*:*:*:*:* Added Reference Type Juniper Networks, Inc.: https://kb.juniper.net/JSA107807 Types: Mitigation, Vendor Advisory -
New CVE Received by [email protected]
Apr. 09, 2026
Action Type Old Value New Value Added Description A UNIX Symbolic Link (Symlink) Following vulnerability in the CLI of Juniper Networks Junos OS allows a local, authenticated attacker with low privileges to escalate their privileges to root which will lead to a complete compromise of the system. When after a user has performed a specific 'file link ...' CLI operation, another user commits (unrelated configuration changes), the first user can login as root. This issue affects Junos OS: * all versions before 23.2R2-S7, * 23.4 versions before 23.4R2-S6, * 24.2 versions before 24.2R2-S3, * 24.4 versions before 24.4R2-S2, * 25.2 versions before 25.2R2. This issue does not affect versions 25.4R1 or later. Added CVSS V4.0 AV:L/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:U/V:X/RE:M/U:X Added CVSS V3.1 AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H Added CWE CWE-61 Added Reference https://kb.juniper.net/JSA107807